Abstract

There has been much recent interest in the use of optical photon echoes for information storage and processing. Unfortunately, existing optical echo memories require doped crystals at liquid He temperature. The proposed scheme uses an optically excited microwave spin echo to store optical temporal information in the Raman excited ground state coherences. The advantage is that microwave echoes are known to exist at room temperature with decay times approaching 1 s in certain materials. We show that these spin echoes can be excited and detected optically, thereby allowing storage densities that are comparable to the optical echo techniques. Briefly, a three level A system is used, which can be excited by two near resonant optical transitions or one near resonant microwave transition. The Raman interaction first stores temporal and phase information in an inhomogeneously broadened ground states coherence. A microwave π-pulse is used to time-reverse the coherences, thus generating spin echoes that can be detected optically by a Raman probe. Preliminary experimental results will also be reviewed.

© 1992 Optical Society of America